Nickel phthalocyanine based organic photo transistor: effect of semiconductor film thickness

Organic semiconducting photo transistors have been fabricated by depositing nickel phthalocyanine (NiPc) and semitransparent thin films of aluminum in sequence by vacuum evaporation on a glass substrate having silver source and drain electrodes. The thickness of NiPc film has been varied as 100 nm, 200 nm and 300 nm. The fabricated organic photo transistors (OPTs) having metal (aluminum)-semiconductor (NiPc) Schottky junction are then characterized and the effects of light irradiation on its characteristics have been investigated. It is observed that the drain current of OPTs rises with increasing radiation intensity and the OPTs having 200 nm thick NiPc film exhibited better performance as compared to the transistors having 100 nm and 300 nm thick films of NiPc